Playing in a rock band can be glamorous, the teachers at Ramona Hall tell their students, but more than anything, the key to success is hard work and discipline.

It's a lesson that has rubbed off well on the members of the Sirens. They practice three days a week at Ramona Hall, and are often booked months in advance.

After Martinez cut off practice for weeks when band members let their grades dip in school, the girls never under- performed in the classroom again.

Among themselves, they have taken care of promoting their website through stickers a friend made in Mexico. With money from paying gigs, they have bought amps and good microphones. "Fifty-fives," Martinez said. "The kind Elvis Presley used to use."

The girls said Martinez's unwavering enthusiasm for music inspired them from the beginning, even when their instrumental skills weren't exactly at rock-star levels.

When they played their first gig at a community festival in Sycamore Grove Park next door, "it was horrible," said lead guitarist Marina Bravo, 15.

"You gotta start somewhere," said Michelle Gascon, 17, the band's drummer, de facto business manager and the oldest member of the group.

The Sirens knew each other from either Ramona Hall or Franklin High School, where "every other kid is in a band," Gascon said. After that first gig, they decided to start practicing in earnest. Soon, they were writing their own music.

Today, some of the original songs in their set include rock-punk tunes such as "Mistake," "Whisper Silence," "Veneno" (Spanish for "poison") and "The Burrito Song."

"We learned the basics, and just applied our own style to it," Gascon said.

As with all successful rock acts, the Sirens catch flak from neighborhood guys for having commercial success, however modest. It goes against Highland Park's deep-bred punk-rock ethos. Besides, they're girls.

"That's what they say, 'You're OK for a girl,' " Bravo said.

Fifteen-year-old bassist Dejah Sandoval, the quieter member of the group, shrugged and nodded.

The Sirens chalk it up to rock-star jealousies and concentrate on playing and practicing. The walls inside Martinez's stuffy teaching room on the second floor of Ramona Hall are covered with pictures of the group, award certificates and posters for events where they have played.

These days, their practice sessions are playful, almost casual. Martinez sometimes goes one-on-one with a Siren, on his own guitar, helping the girls through one or two especially difficult chord changes.